declare @tItem table
(idx int identity, paymentH int, amt decimal(10,2));

insert into @tItem(paymentH, amt) values(14, 200);
insert into @tItem(paymentH, amt) values(14, 50);
insert into @tItem(paymentH, amt) values(14, 50);
/*the relationship for paymentH to amt is a 1 to many*/


declare @paymentH int
set @paymentH=14
declare @paymentItem xml
set @paymentItem='<data>
<paymentItem><amt>200</amt></paymentItem>
<paymentItem><amt>150</amt></paymentItem>
<paymentItem><amt>30</amt></paymentItem>
</data>'

/*
1. How to updating @tItem with the @paymentItem where paymentH=14?
2. Based on above data, only amt=150 and amt=30 need to be updated
3. The rest is remain and no need to be updated
*/